SIGNIFICANT ACCOUNTING POLICIES - FISCAL YEAR (Details)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
SIGNIFICANT ACCOUNTING POLICIES
Fiscal Period Duration	364 days	371 days	364 days

Duration of a fiscal period, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Includes, but not limited to, weeks in a year or quarter.

No definition available.

Name:	us-gaap_FiscalPeriodDuration
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration